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• Video capturing in portrait mode but the orientation is wrong when played back with a media player

  17 octobre 2016, par Ahmed Mujtaba

  I’m trying to make a custom video app. The app captures a video using mediarecorder and uploads it to the website where it’s played on a html5 media player. The issue is that, when I capture the video in portrait mode, the playback video on the website and on vlc player have it’s orientation off by 90 degrees. I have tried various solution on the internet but none work for me.

  Here’s what my code for setting up the media recorder :

   private bool prepareMediaRecorder() {
  
  
  
          Android.Hardware.Camera.Parameters p = mCamera.GetParameters();
  
          List previewSizes = p.SupportedPreviewSizes.ToList();
  
  
  
          //mCamera = GetCameraInstance();
  
          //setCameraDisplayOrientation(Activity, cameraId, mCamera);
  
  
  
          mediaRecorder = new MediaRecorder();
  
          mCamera.Unlock();
  
          mediaRecorder.SetCamera(mCamera);
  
  
  
          mediaRecorder.SetAudioSource(AudioSource.Camcorder);
  
          mediaRecorder.SetVideoSource(VideoSource.Camera);
  
          mediaRecorder.SetOrientationHint(CameraS.result);
  
  
  
          if (currentapiVersion >= 16)
  
          {
  
              mediaRecorder.SetProfile(CamcorderProfile.Get(CamcorderQuality.High)); // requires API Level 8 or higher
  
          }
  
          else
  
          {
  
              mediaRecorder.SetProfile(CamcorderProfile.Get(CamcorderQuality.Q480p)); // requires API Level 8 or higher
  
          }
  
  
  
          //mediaRecorder.SetVideoFrameRate(30);
  
          mediaRecorder.SetOutputFile(localPath);
  
          mediaRecorder.SetMaxDuration(600000); // Set max duration 60 sec.
  
          mediaRecorder.SetMaxFileSize(50000000); // Set max file size 50M
  
          mediaRecorder.SetVideoSize(previewSizes[0].Width, previewSizes[0].Height);
  
          mediaRecorder.SetPreviewDisplay(mPreview.Holder.Surface);
  
  
  
          mediaRecorder.SetOrientationHint(getDisplayOrientationAngle());
  
  
  
          try
  
          {
  
              mediaRecorder.Prepare();
  
          }
  
          catch (IllegalStateException e)
  
          {
  
              releaseMediaRecorder();
  
              return false;
  
          }
  
          catch (Java.IO.IOException e)
  
          {
  
              releaseMediaRecorder();
  
              return false;
  
          }
  
          return true;
  
  
  
  }
  
  
  
  public int getDisplayOrientationAngle() {
  
          //Log.e("", "setDisplayOrientationAngle is call");
  
          int angle;
  
  
  
  
  
          var mDisplayRotation = Activity.WindowManager.DefaultDisplay.Rotation;
  
          // switch (MeasurementNativeActivity.DisplayRotation) {
  
          switch (mDisplayRotation)
  
          {
  
              case SurfaceOrientation.Rotation0: // This is display orientation
  
                  angle = 90; // This is camera orientation
  
                  break;
  
              case SurfaceOrientation.Rotation90:
  
                  angle = 0;
  
                  break;
  
              case SurfaceOrientation.Rotation180:
  
                  angle = 270;
  
                  break;
  
              case SurfaceOrientation.Rotation270:
  
                  angle = 180;
  
                  break;
  
              default:
  
                  angle = 90;
  
                  break;
  
          }
  
          //Log.v("", "media recorder displayRotation: " + mDisplayRotation);
  
          //Log.v("", "media recorder angle: " + angle);
  
          return angle;
  
  
  
  }

  The orientation of the video is fine when played on the phone app but on the website it’s not. I tried to use FFMPEG encoder to rotate the video clockwise. This seemed to fix the orientation of the video, however the aspect ratio of the video is all messed up. The video is stretched vertically and goes off screen.
  The command I’m using to rotate and encode the video is as follows :

  -y -i inputPath -vf scale=640:480,setsar=1,transpose=1 -strict experimental -r 25 -vcodec mpeg4 -b 1000k ab 48000 -ac 2 -ar 22050 destinationPath

  I will really appreciate if someone can help me fix either the orientation of the video or the aspect ration after encoding the video.

  Cheers !

  Edit.

  Here’s the readout of the input file :

  General
  
  Complete name                  : C:\Users\Ahmed\Desktop\9adcdb56-500e-4d3f-8fb2-ccf20c680422_yt.mp4
  
  Format                         : MPEG-4
  
  Format profile                 : Base Media
  
  Codec ID                       : isom
  
  File size                      : 6.30 MiB
  
  Duration                       : 12s 437ms
  
  Overall bit rate               : 4 251 Kbps
  
  Encoded date                   : UTC 2016-05-29 23:54:30
  
  Tagged date                    : UTC 2016-05-29 23:54:30
  
  
  
  Video
  
  ID                             : 1
  
  Format                         : AVC
  
  Format/Info                    : Advanced Video Codec
  
  Format profile                 : Baseline@L3.1
  
  Format settings, CABAC         : No
  
  Format settings, ReFrames      : 1 frame
  
  Format settings, GOP           : M=1, N=31
  
  Codec ID                       : avc1
  
  Codec ID/Info                  : Advanced Video Coding
  
  Duration                       : 12s 323ms
  
  Bit rate                       : 3 967 Kbps
  
  Width                          : 1 280 pixels
  
  Height                         : 720 pixels
  
  Display aspect ratio           : 16:9
  
  Rotation                       : 90°
  
  Frame rate mode                : Variable
  
  Frame rate                     : 29.700 fps
  
  Minimum frame rate             : 29.354 fps
  
  Maximum frame rate             : 30.040 fps
  
  Color space                    : YUV
  
  Chroma subsampling             : 4:2:0
  
  Bit depth                      : 8 bits
  
  Scan type                      : Progressive
  
  Bits/(Pixel*Frame)             : 0.145
  
  Stream size                    : 5.83 MiB (92%)
  
  Title                          : VideoHandle
  
  Language                       : English
  
  Encoded date                   : UTC 2016-05-29 23:54:30
  
  Tagged date                    : UTC 2016-05-29 23:54:30
  
  
  
  Audio
  
  ID                             : 2
  
  Format                         : AAC
  
  Format/Info                    : Advanced Audio Codec
  
  Format profile                 : LC
  
  Codec ID                       : 40
  
  Duration                       : 12s 437ms
  
  Source duration                : 12s 454ms
  
  Bit rate mode                  : Constant
  
  Bit rate                       : 128 Kbps
  
  Nominal bit rate               : 96.0 Kbps
  
  Channel(s)                     : 2 channels
  
  Channel positions              : Front: L R
  
  Sampling rate                  : 48.0 KHz
  
  Compression mode               : Lossy
  
  Stream size                    : 194 KiB (3%)
  
  Source stream size             : 194 KiB (3%)
  
  Title                          : SoundHandle
  
  Language                       : English
  
  Encoded date                   : UTC 2016-05-29 23:54:30
  
  Tagged date                    : UTC 2016-05-29 23:54:30
  
  mdhd_Duration                  : 12454

• Dynamic subtitles by ffmpeg

  8 septembre 2019, par Saeron Meng

  I would like to add some commentary texts into my video but I do not know how to use ffmpeg to realize this. The comments are like screen bullets through the screen, appearing in the right margin, moving and scrolling, and disappearing from the left.

  My thought is to count the length of the comments and define speeds for them to move and I have already gotten the comments saved as an xml file. But even though I can transfer it into srt file, the tricky problem is, it is hard to write the speeds of the subtitles, or something like that, in an srt file, and apply them to ffmpeg commands or APIs. Here is an example of comments (xml file) :

  <chat timestamp="671.195">
  
      <ems utctime="1562584080" sender="Bill">
  
          <richtext></richtext>
  
      </ems>
  
  </chat>
  
  <chat timestamp="677.798">
  
      <ems utctime="1562584086" sender="Jack">
  
          <richtext></richtext>
  
      </ems>
  
  </chat>

  The final result is like this (I did not find an example in websites in English. In China, such moving subtitles are called "danmu" or "screen bullets"), these colorful characters can move horizontally from right to left :

  

  1. I have searched some solutions on the Internet, most of which talk about how to write ass/srt files and add motionless subtitles. Like this :

  ffmpeg -i infile.mp4 -i infile.srt -c copy -c:s mov_text outfile.mp4

  3
  
  00:00:39,770 --> 00:00:41,880
  
  When I was lying there in the VA hospital ...
  
  
  
  4
  
  00:00:42,550 --> 00:00:44,690
  
  ... with a big hole blown through the middle of my life,
  
  
  
  5
  
  00:00:45,590 --> 00:00:48,120
  
  ... I started having these dreams of flying.

  But I need another kind of "subtitles" which can move.

  2. When it comes to scrolling subtitles, there are still some solutions : Scrolling from RIGHT to LEFT in ffmpeg / drawtext

  So my question is, how to combine the solutions above to arrange subtitles from top to bottom and let them move concerning the timestamps of the comments ?

• ffmpeg : two videos side-by-side with audio1 lang=ger & audio2 lang=eng

  19 janvier 2023, par miridigital

  I have two videos from two GoPro cameras. Both videos are rendered via ffmpeg side-by-side into a single video (left and right) and the audio is currently combined/mixed into two channels (stereo). I can hear both camera audio channels at the same time.

  


  Two channels stereo :

  


  ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]; [0:a][1:a]amerge[a]" -map "[v]" -map "[a]" -ac 2 side-by-side.mp4


  


  audio from both videos mixed into a single file with 2 channels - mediainfo

  


  Now I want to switch between the two audio channels (cam1 or cam2) while I'm playing the side-by-side video.

  


  My first try : With four channels (without -ac 2 parameter) :

  


  ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]; [0:a][1:a]amerge[a]" -map "[v]" -map "[a]" side-by-side.mp4


  


  audio from both videos mixed into a single file with 4 channels - mediainfo

  


  But the most video players can't easily select the channels 1+2 or 3+4 while playing.

  


  So I tried two languages :

  


  ffmpeg -i video1.mp4 -i video2.mp4 -filter_complex "[0:v][1:v]hstack=inputs=2[v]; [0:a][1:a]amerge[a]" -map "[v]" -map "[a]" -metadata:s:a:0 language=ger -metadata:s:a:1 language=eng side-by-side.mp4


  


  audio from both videos mixed into a single file with 4 channels with languages - mediainfo

  


  But that's wrong. I can only see german with 4 channels. How can I put channels 1+2 into german and channels 3+4 into english ? Afterwards I should be able to use the multi language feature from most video players to switch the audio between cameras.

  


  Thank you,
  
Miriam